Rectangular metal-tubing bender

ABSTRACT

A rectangular tubing bender having a frame provided with an arrangement for locking in place a tube to be bent. Structure on the frame forms directly opposed depressions on opposite sides of the rectangular tube prior to bending of the tube adjacent the depressions for permitting a completely closed and square bend to be formed. The locking arrangement may be mounted on a carriage movable on the frame for bending the tube by moving same against a stationary forming point member subsequent to the formation of the depressions in the tube. Cam operated rockers are advantageously employed to form the depressions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is related generally to the bending of tubing, andparticularly to the formation of bends in rectangular tubing, and thelike, that are completely closed and square on the inside of the bend.

2. Description of the Prior Art

Conventional devices commonly employed for forming right-angle andsimilar bends in metal tubing having a rectangular cross section form anopen bend which decreases the strength and rigidity of the element andmakes it difficult to weld at the inside corner of the tube at the bendtherein in order to additionally strengthen the bent tube.

Prior U.S. Pat. Nos. believed pertinent to this invention are asfollows:

    1,816,218        July 28, 1931                                                2,148,748        Feb. 28, 1939                                                2,516,372        July 25, 1950                                                2,835,306        May 20, 1958                                                 3,042,099        July 3, 1962                                                 3,073,372        Jan. 15, 1963                                                3,240,048        Mar. 15, 1966                                                3,472,055        Oct. 14, 1969                                            

SUMMARY OF THE INVENTION

It is an object of the present invention to provide rectangular tubingwith completely closed and square bends for forming a more rigid,stronger bend, and making it possible to weld the inside corner of thebend for additional strength.

It is another object of the present invention to provide for the bendingof rectangular tubing, and the like, in a simple, efficient andconsistent manner.

These and other objects are achieved according to the present inventionby bends formed by first depressing, or dimpling, a section of a tube tobe bent on two opposing sides thereof to form directly opposed dimplesin the tube; then moving the dimpled tube toward a forming point; andbending the dimpled tube on the forming point.

Apparatus according to the present invention for forming theaforementioned bends includes: a frame; a holding arrangement forlocking a rectangular tube to be bent in place on the frame; a squeezingarrangement for forming the depressions on opposite sides of the tube;and a forming member for bending the tube about the depressions formedtherein.

The holding arrangement advantageously includes a carriage mounted onthe frame for reciprocal movement with respect to the frame, and asupport member mounted on the carriage. The support member includes apair of substantially parallel, opposed, spaced flanges connectedtogether by a web, with the flanges being arranged for receiving betweenthem a tube to be bent.

The forming arrangement advantageously further includes a forming pointmember affixed to the frame and arranged for cooperating with thesupport member to bend a tube to be bent. Accordingly, the holdingarrangement preferably further includes drive means for sequentiallymoving the carriage toward the forming point member.

A preferred embodiment of the squeezing arrangement includes a pair ofrockers pivotally mounted about substantially parallel axes on thecarriage whereby each rocker is provided with a pair of arms. Asqueezing jaw is mounted on a one arm of a rocker, and a cam follower ismounted on the other of the arms. The jaws and cam followers of therockers are arranged in opposed relationship to one another, and cams,which may be in the form of ramps mounted on the forming point member,operatively engage the cam followers and pivot the jaws towards oneanother for forming the depressions in the tube.

The holding arrangement preferably further includes a pair of platesarranged bracketing the support member, and a pair of lock arms arepivotally mounted on the carriage for selectively engaging the platesand preventing same from spreading apart as the cam followers contactthe cam following ramps referred to above. In this manner, the tubebeing bent is securely held on the carriage as the various operationsare being performed on the tube.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a tubing bender according to thepresent invention.

FIG. 2 is a fragmentary, sectional view taken generally along the line2--2 of FIG. 1.

FIG. 3 is a fragmentary, perspective view showing a detail of the deviceof FIGS. 1 and 2.

FIG. 4 is a fragmentary, top plan view showing the detail of FIG. 3, butwith the parts thereof in a moved position.

FIG. 5 is a fragmentary, vertical, longitudinal sectional view, similarto FIG. 2, but showing certain parts in a moved position from FIG. 2.

FIG. 6 is a fragmentary, top plan view, partly broken away, similar toFIG. 4, but showing certain parts thereof in a moved position from theirposition in FIG. 4.

FIG. 7 is a fragmentary, sectional view taken generally along the line7--7 in FIG. 5.

FIGS. 8, 9, and 10 are fragmentary, perspective views showing thesequence of steps in forming a bend in rectangular tubing in accordancewith the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 of the drawings shows a rectangular tubing bender 10 according tothe present invention which includes a frame 12 provided with anarrangement 14 for holding a tube 16 of rectangular cross section. Asqueezing arrangement 18 is also provided on frame 12 for formingdepressions, or dimples, on opposite sides of tube 16 prior to bendingof the tube 16 by means of a forming arrangement 20. The tube is bentabout the previously formed depressions in a manner to be described ingreater detail below.

Referring now more particularly to FIGS. 2 through 4 of the drawings,arrangement 14 includes a carriage 22 slidably mounted on frame 12 forreciprocal movement with respect to the frame. A support member 24 ismounted on carriage 22, and includes a pair of substantially parallel,opposed, spaced flanges 26 and 28 connected together by a web 30.Flanges 26, 28 are arranged for receiving therebetween tube 16.

Arrangement 20 advantageously further includes a forming point member 32affixed to frame 12 in a conventional manner and arranged forcooperating with support member 24 to bend tube 16. Toward this end,arrangement 14 further includes a drive motor 34, which isadvantageously the illustrated linear fluid motor, connected to carriage22 as by piston rod 36 for sequentially moving carriage 22 towardforming point member 32. As will be appreciated, motor 34 will alsoretract carriage 22 from the proximity of member 32.

Squeezing arrangement 18 advantageously includes a pair of rockers 38and 40 pivotally mounted on carriage 22 for pivoting about suitableaxles such as the illustrated pins 42 and 44. As can be readilyappreciated from, for example, FIG. 2 of the drawings, rockers 38 and 40are pivotally mounted on pins 42, 44 at points on the rockers betweenthe ends of same for providing each rocker with a pair of arms.Squeezing jaws 46 and 48 are mounted on one arm of the rockers, whilecam followers 50, 52 are mounted on the other arm of the rockers. Jaws46, 48 and cam followers 50, 52 are arranged opposite one another foroperatively engaging a pair of oppositely directed ramps affixed to theforming point member 32 and forming cams that pivot the jaws 46, 48toward one another and cause them to form the depressions in tube 16.

Arrangement 14 still further includes a pair of plates 58 and 60, whichmay have the generally diamond-shaped configuration best seen perhaps inFIG. 4 of the drawings, arranged bracketing support member 24. The freeend of piston rod 36 of motor 34 is pivotally connected to plates 58, 60as by a conventional hinge 62. A pair of lock arms 64 and 66 arepivotally mounted on carriage 22 for selectively engaging plates 58 and60 and preventing same from spreading apart as cam followers 50, 52engage the cam forming ramps 54 and 56. A crank 68 is affixed to a shaft70 to which arms 64 and 66 are also affixed. Shaft 70 is pivotallymounted in suitable brackets 72 as can be seen from FIG. 7 of thedrawings. Coiled torsion springs 74 are associated with brackets 72 in aconventional manner for retaining arms 64 and 66 in their upright, orlocking, position as shown in FIG. 3 of the drawings. A pin 76 isprovided projecting from a beam 78 partially forming frame 12 forengaging crank 68 when carriage 22 is in a retracted position, as shownin FIGS. 2 and 4 of the drawings, and swinging arms 64 and 66 into theposition shown in FIG. 2 for arm 66. This position is an inoperativeposition of the lock arms 64, 66 which permits the tube 16 to be removedfrom, and another tube placed into, support member 24. Notches 80 areprovided in arms 64 and 66 for permitting the arms to positively engageplates 58 and 60 and prevent the plates from spreading. Further, notches82 are provided in arms 64, 66 for mating with tubes 16 as can best beseen from FIG. 5 of the drawings.

Referring again to FIG. 7 of the drawings, frame 12 further includes apair of angles 84 and 86 forming spaced, substantially parallel, siderails of the frame. Beam 78 and a similar beam 88 are attached to therespective angles 84 and 86. As can best be seen from FIG. 3, a cutoutportion 89 is provided in angle 86 for receiving crank 68. A plate 90 isattached to brackets 72, which in turn slide beneath beams 78 and 88,and is provided with a pair of projections 92 and 94 which journal shaft70. As also can best be seen from FIG. 7, rocker 40 is provided with apair of spaced, substantially parallel portions 96 and 98 which receivecam follower 52. The latter is rotatably mounted on a rod 100 journaledin portions 96 and 98. It will be appreciated that rocker 38 isconstructed in a similar manner.

Point member 32 is advantageously mounted in a conventional manner, suchas by the illustrated bolt, to a crossbar 102 which is arrangedextending between the beams 78 and 88. Grooves 104 and 106 are providedin point member 32 extending longitudinally away from the ramps 54 and56 for forming a guide path for the cam followers 50, 52 and permittingthe followers to move toward one another a distance sufficient to assurethat the jaws 46 and 48 will clear tube 16 once the depressions havebeen made in the tube.

Guides 108 and 110, which are advantageously in the form of metalplates, and the like, are desirably provided in those portions of beams78 and 88 traversed by carriage 22. In this manner, the lower surface ofplate 60 and the uppermost portion of brackets 72 will act as slideswhich permit the carriage 22 to be moved in a rigid and stable manneralong frame 12.

As best seen from FIGS. 1 and 3 of the drawings, an installation isprovided which includes a crossbar 112 and beams 114 and 116 extendingcantilever fashion perpendicular to bar 112 for supporting a curved rail118 that prevents the tubing from dropping as the bend is being made.This also eliminates placing undue stress on the machine. Curved rail118 has associated therewith a pair of guide bars 120 and 121 upon whichthe tube 60 is arranged prior to its being bent. A fixed stop 122 isarranged at the outermost end of guide bar 121, while an adjustable stopand alignment assembly 124 is provided for positioning tubing being bentto allow for varying placement of the bends. Assembly 124 is mounted onguide bar 121 in a manner that permits it to be adjusted along thelength of the bar. This mounting may be achieved as by a conventionalclamp mounting of the assembly, which mounting is shown schematically inFIG. 1.

Referring again to FIG. 1, a conventional electric motor 126, and thelike, is connected to a conventional source of electric power (notshown) to actuate a conventional fluid pump 128. The output of pump 128is situated through hoses 130 and 132 to motor 34 for the purpose ofactuating same. A linkage 134 connects in a conventional manner anoperator's handle 136 to the conventional control mechanism (not shown)of pump 128. In this manner, an operator (not shown) may actuate motor34 by manipulation of handle 136 in a known manner.

As can best be seen from FIGS. 4 and 6 of the drawings, support member24 is divided into a pair of similar portions 138 and 140. Each of theseportions 138, 140 is pivotally mounted between plates 58 and 60 as bypins 142 and 144 which may be in the form of the illustrated bolts.Further, each of the portions 138 and 140 has a flange 26, 28 and aconnecting web 30. Thus, when tube 16 is bent by engagement therewithagainst point member 32, portions 138 and 140 will be swung around pins142 and 144 to a position forming a substantial V-shape as is shown inFIG. 6. When tube 16 is first placed within support member 24, however,the webs 30 will be parallel to tube 16 as is seen in FIG. 4.

OPERATION

The operation of a bender 10 according to the present invention will nowbe described with reference to FIGS. 5, 6, and 8 through 10 of thedrawings.

A tube 16 is initially loaded into support member 24 with the carriage22, and lock arms 64 and 66, in the positions shown in FIG. 2 of thedrawings. Motor 34 is now actuated and carriage 22 is fed toward formingpoint member 32. When carriage 22 has traversed toward point member 32sufficiently to permit the cam followers 50 and 52 to engage theirassociated ramps 54 and 56, as shown in FIG. 5, jaws 46 and 48 will bebrought toward one another by a pivoting movement of rockers 38 and 40about their associated pins 42 and 44, and a pair of directly opposeddepressions 146 will be formed in opposite walls of tube 16. Thesedepressions are advantageously substantially in the transverse centerportion of the associated walls of the tube. As carriage 22 continuesits movement to the right as seen in FIG. 5, cam followers 50 and 52will fall into their associated grooves 104 and 106, an extreme positionof which is shown in FIG. 6 of the drawings. When the cam followers 50,52 pass into grooves 104, 106, carriage 22 will have moved sufficientlyfar to the right as viewed in FIG. 5 to cause the V-shaped point offorming point member 32 to engage tube 16 at a point immediatelyadjacent the depressions and in a wall adjacent the forming member 32and perpendicular to the walls in which the depressions were made. Itwill be appreciated that once the cam followers 50, 52 pass into grooves104, 106 jaws 46, 48 will be released from tube 16. Contact of tube 16with forming point 32 will cause the tube to start to bend as is seen inFIG. 8. Continued movement of carriage 22 toward the right in FIG. 5will cause additional bending of tube 16, as is shown in, for example,FIG. 9. Both depressed sides of tube 16 bend inward as the bendingproceeds. Further, the area where the forming point member 32 contactstubing 16 also bends inwardly. This is apparent from FIG. 9. As tube 16is bent further, the bend on the inside of the tubing forces formingpoint member 32 out of the inside bend, thus allowing completion of thebend as shown in FIGS. 6 and 10 of the drawings. In this manner, a bendis formed which is closed and square on the inside 148 of the bend, thusmaking it possible to weld the inside corner of the bend for additionalstrength.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

I claim:
 1. A rectangular tubing bender, comprising, in combination:a. aframe; b. holding means for locking a rectangular tube to be bent inplace on the frame; c. squeezing means for forming depressions onopposite sides of the tube; d. forming means for bending the tube into aclosed corner about the depressions therein; and the holding means (b)includes a carriage mounted on the frame for reciprocal movement withrespect to the frame, and a support member mounted on the carriage, thesupport member including a pair of pivotally mounted portions, eachportion including a pair of substantially parallel, opposed, spacedflanges connected together by a web, the flanges being arranged forreceiving therebetween a tube to be bent, and the web being arranged forforming substantially a V-shape to conform to the tube as same is beingbent by the forming means; and the forming means (d) further includes aforming point member affixed to the frame and arranged for cooperatingwith the support member to bend a tube to be bent, and the holding means(b) further including drive means for sequentially moving the carriagetoward the forming point member; and the squeezing means (c) includes apair of rockers pivotally mounted on the carriage about substantiallyparallel axes arranged between ends of the rockers for providing eachrocker with a pair of arms, a squeezing jaw mounted on one arm and a camfollower mounted on the other arm, the jaws, and cam followers, arrangedopposite one another, and cam means mounted on the frame for operativelyengaging the cam followers and pivoting the jaws toward one another andforming depressions in the tube.
 2. A structure as defined in claim 1,wherein the cam means includes a pair of oppositely directed rampsaffixed to the forming point member.
 3. A structure as defined in claim2, wherein the holding means further includes a pair of plates arrangedbracketing the support member, fastener means for pivotally connectingthe plates to one another and to the piston rod, and a pair of lock armspivotally mounted on the carriage for selectively engaging the platesand preventing same from spreading apart as the cam followers engage thecam forming ramps.
 4. A structure as defined in claim 3, wherein thedrive means includes a linear fluid motor having a piston rod connecteddirectly to the carriage.
 5. A rectangular tubing bender, comprising, incombination;a. a frame; b. holding means for locking a rectangular tubeto be bent in place on the frame; c. squeezing means for formingdepressions on opposite sides of the tube; the squeezing means includesa pair of rockers pivotally mounted about substantially parallel axesarranged between ends of the rockers for providing each rocker with apair of arms, a squeezing jaw mounted on one arm and a cam followermounted on the other arm, the jaws, and cam followers, arranged oppositeone another, and cam means mounted on the frame for oppositely engagingthe cam followers and pivoting the jaws toward one another and formingdepressions in the tube; d. forming means for bending the tube into aclosed corner about the depressions therein; and the holding means (b)includes a carriage mounted on the frame for reciprocal movement withrespect to the frame, and a support member mounted on the carriage, thesupport member including a pair of pivotally mounted portions, eachportion including a pair of substantially parallel, opposed, spacedflanges connected together by a web, the flanges being arranged forreceiving therebetween a tube to be bent, and the web being arranged forforming substantially a V-shape to conform to the tube as same is beingbent by the forming means; and the holding means further includes a pairof plates arranged bracketing the support member, fastener means forpivotally connecting the plates to one another and to the piston rod,and a pair of lock arms pivotally mounted on the carriage forselectively engaging the plates and preventing same from spreading apartas the cam followers engage the cam forming ramps.
 6. A rectangulartubing bender, comprising, in combination;a. a frame; b. holding meansfor locking a rectangular tube to be bent in place on the frame; c.squeezing means for forming depressions on opposite sides of the tube;d. forming means for bending the tube into a closed corner about thedepressions therein; and the squeezing means (c) includes a pair ofrockers pivotally mounted about substantially parallel axes arrangedbetween ends of the rockers for providing each rocker with a pair ofarms, a squeezing jaw mounted on one arms and a cam follower mounted onthe other arm, the jaws, and cam followers, arranged opposite oneanother, and cam means mounted on the frame for oppositely engaging thecam followers and pivoting the jaws toward one another and formingdepressions in the tube.
 7. A structure as defined in claim 5, whereinthe cam means includes a pair of oppositely directed ramps affixed to aforming point member of said forming means.